OK, I will have to make an educated guess: you get that error when you are trying to restore your site's database. I will tell you what the problem is, why it's not resolved and how to work around it.
This is a conflict with Rochen's server setup. They are using mod_security2 with very strict settings on their server. It is supposed to block suspicious requests. However the very strict settings they use also block requests containing complex database passwords, i.e. passwords which contain non-alphanumeric characters like an exclamation mark, at-sign, hash, dollar, percent sign, caret, ampersand and so on.
I have already discussed that with Rochen, a little over two years ago. We have tried to work out a solution, but it was impossible. They insisted that allowing such complex database passwords would result in security degradation for their servers.
And here's the workaround. Log into your site's cPanel (http://www.example.com:2083, where www.example.com is to be substituted with your site's domain name) and click on MySQL Databases. Find the database user in use and change its password. Create a password which is 8 to 14 characters long but only consists of lowercase letter, uppercase letters and numbers (a-z, A-Z and 0-9). Use this new password when restoring your site and the restoration will go through.
AFAIK this issue affects all scripts which need the database password, including Joomla!'s and WordPress' own web-based installation scripts. Since Akeeba Backup Installer (the site restoration script) works just like Joomla!'s web-based installer it is affected by the same security setting as all of the other scripts.
Nicholas K. Dionysopoulos
Lead Developer and Director
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